供热机组经济性指标简化计算方法

Simplified calculation method for economical indexes of heating units

供热机组经济性指标的精确核算任务繁重、工作量大。对此提出了一套经济性指标的简化计算方法,以便对机组经济性指标的变化进行快速核算。针对抽汽供热机组、采用余热回收装置的供热机组和高背压循环水供热机组3种类型的供热机组,以供热比、发电热耗率的核算为例进行详细说明。并与全面性热力计算结果进行对比。结果表明:采用简化方法核算的对外供热量与全面性热力计算的结果具有相当好的一致性,对于核算的机组功率及机组热耗率二者最大相差仅约0.9%,当供热量较小时,二者相差会进一步减小,故能够很好满足工程估算的要求;对于高背压循环水供热机组,采用电动给水泵时机组热耗率约3 650 k J/(k W?h),采用汽动给水泵时机组热耗率约3 720 k J/(k W?h);与抽汽供热机组相比,高背压循环水供热机组的热耗率下降幅度较大。

In order to rapidly calculate the change of the unit economical index, this paper presents a set of the simplified calculation method for economic indexes of the extraction steam heating units, the heating units with the waste heat recovery device and the heating units with high back pressure circulating water. Moreover, the results calculated by this method were compared with that by the comprehensive thermodynamic calculation methods. The results show that, the heat supply quantity calculated by this simplified method has a very good consistency with that by the comprehensive calculation results, and the largest difference between them is only about 0.9% for unit power and heat rate. When the heat supply quantity is small, the difference will be further reduced, so it can meet the demands of engineering calculation very well. For heating units with high back pressure circulating water, the heat rate of the unit with electric feedwater pump is about 3 650 kJ/（kW.h）, and that of the unit with steam feedwater pump is about 3 720 kJ/（kW.h）. Compared with the extraction steam heating units, the heat rate of the unit with high back pressure circulating water heating decreases more significantly.